Field of the Invention
The present invention relates to an interference measuring device that performs measurement, which makes use of brightness information of the interference fringes generated by the interference of light.
Description of the Related Art
Conventionally, interference measuring devices, such as three-dimensional shape measuring devices that measure, for example, the three-dimensional shape of a measuring object in a precise manner by making use of brightness information of the interference fringes generated by the interference of light, are known.
For example, in an interference measuring device that makes use of a white-light light source, at a focused positon where the optical path lengths of a reference optical path and a measurement optical path match each other, the peaks of the interference fringes of the respective wavelengths are superimposed onto each other and the brightness of the combined interference fringes increases. Accordingly, in the interference measuring device, by capturing, with an imaging element such as a CCD camera or the like, an interference image that indicates a two-dimensional distribution of the interference light intensities while varying the optical path length of the reference optical path or the measurement optical path, and, by detecting a focused position at which the interference light intensities reach their peaks at the respective measurement positions within a capturing field of view, it is possible to measure a height of a measurement surface in a corresponding measurement position and thus a three-dimensional shape or the like of the measuring object (see, for example, JP2011-191118A).